.The Pilot Core (Core B) will develop and conduct innovative research projects examining the ways in which social networks are related to health, health behavior, and well being more generally. Below, we sketch out the kinds of ideas we hope to explore and provide more detail regarding four sample pilots that illustrate the types of research we will conduct under the auspices of the proposed Harvard Roybal Center. These four, one-year pilot projects fall into two categories: (1) studies that use online social networks to advance understanding of the role of network structure and processes in health and well being; and (2) studies that examine the flow of behaviors and health states within the unique Framingham Heart Study Social Network (FHS-Net) in order to better understand how health and illness spread within a population. Future pilot projects may of course move beyond these foci, though they will remain focused on social networks and well being. Our pilots interpret the notion of well being broadly. Possible measures of well being reflect several constructs, improvement in any one of which might be said to enhance human well being: Health Health behavior Subjective affective states or traits (such as happiness) Quality of life Social connections and social engagement Our overall objective is to translate our prior discoveries about how networks form and operate into a better understanding of the ways in which they might be exploited to enhance well being. We believe this research has great potential to influence interventions to improve the well being of older people through a more comprehensive understanding of social influences on health behaviors and a more comprehensive elucidation of how these influences depend on people's embeddedness in social networks. This embeddedness means that the health of one person affects the healt h of others. Illness, health behavior, or death in one person can contribute to similar outcomes in others, through a non-biological spread of disease. The existence of such health linkages - including those between relatives, friends, co-workers, and neighbors - suggests rethinking aspects of health policy, clinical care, and research. This approach to the study of health phenomena in complex network architectures can shed new light on many important problems, including obesity and epidemics of bad health behaviors; health disparities; cost-effectiveness assessments of clinical and policy interventions; and the efficacy of community-based interventions. Exploring these critical health care issues, while taking into account the important complexity of large and evolving networks of people, will require pioneering methods. Indeed, even the types of data required to study such phenomena will need to be markedly different from the data heretofore commonly used in healthcare research. But studying such phenomena from a social network perspective will yield important new insights that will be very useful in preventing and treating serious health problems facing the U.S. today. It is with this need for new ideas, methods, and data sources in mind that we aspire to create this Roybal Center in order to conduct innovative pilot research projects applying network science to the study of health and well being and in order to translate network science findings to benefit public health. In keeping with the aim of the Roybal program to improve the lives of older people and the capacity of institutions to adapt to societal aging, we see a great deal of potential in many areas of emphasis touched by the pilots below to improve the health and well being of older people. Classic research on social networks and health outcomes has demonstrated the profound impact of social ties on the health of the individual, showing that social isolation, especially among older individuals, is related to greater risk of illness and mortality.[1] Yet much remains to be learned about the mechanisms underlying social network effects on the onset and course of illness or, conversely, how social networks enhance and well being. The overarching goal of these pilot projects is to enhance the knowledge base on this subject so that we move closer to an understanding of social context effects that will suggest appropriate policy interventions to make the later years of life healthier, both physically and psychologically.